On the SmartyCode.com site there's a quick new post about making your Zend Framework site a bit more "green" with a conditional GET feature.

In this article I'll show you a simple approach to enable your Zend Framework application saving lots of precious bandwidth, and thus, making it more end-users friendly, and save on bandwidth costs. This technique involves HTTP conditional GET. This is basically a feature of the HTTP protocol. By sending correct HTTP headers with your application, you enable browsers of your end users to cache pages of your site.

A plugin for the front controller (with a dispatchLoopShutdown method inside) is used to handle the requests and cache their content correctly. They have the cache set at 7200 seconds (2 hours) for a time to live, but its easy to tweak it based on your application. TO use the plugin call the registerPlugin function on the controller object and add it as the very last thing that runs.